1983: PCR Invented

PCR - the polymerase chain reaction - is a technique for amplifying DNA that dramatically boosted the pace of genetic research. In a matter of a few hours, PCR can make billions of copies of a specific segment of DNA.

Family studies show that the Huntington's disease gene is linked to a polymorphic DNA marker that maps to human chromosome 4. The chromosomal localization of the Huntington's disease gene is the first step in using recombinant DNA technology to identify the primary genetic defect in this disorder.